This invention concerns transhalogenation between fluoroolefins. This type of exchange reaction, a special case of which is known as disproportionation, has been employed in the art primarily with chlorofluoroalkanes but not with fluoroolefins. One exception, U.S. Pat. No. 3,081,358, discloses the disproportionation of alkenes, specifically chloropentafluoropropenes, to hexafluoropropene and 1,1-dichlorotetrafluoropropene-1 in the presence of a specially prepared aluminum fluoride catalyst. The catalyst is not employed in the process of this invention.
A number of publications disclose the more common disproportionation of chlorofluoroalkanes. Those whcih use an alumina or aluminum fluoride catalyst include U.S. Pat. Nos. 3,087,976, 2,767,227, 2,637,748, 2,478,932, 2,676,996, and 2,478,201. Other catalysts have been employed in the disproportionation of alkanes include:
Alumina activated by pretreatment with a fluorochloroalkane or hexafluoropropene: U.S. Pat. Nos. 3,138,559, 3,087,975, and 3,087,974 and Japanese Pat. No. 43-27748;
Aluminum chloride on alumina: U.S. Pat. No. 2,694,739;
Aluminum fluoride which contains selected amounts of zinc, chromium, nickel and iron: U.S. Pat. Nos. 3,973,229, 3,787,331 and 3,650,987;
Chromiun oxide on activated carbon: E. German Pat. No. 117,444;
Zinc spinel: Russian Pat. No. 636,216;
Copper aluminate spinel: Russian Pat. No. 555,080;
Zirconium tetrachloride: Chem. Abstracts 101, 130215 (1984);
Zinc, cadmium and mercury: Chem. Abstracts 82, 155162 (1975);
Copper: Chem. Abstracts 85, 93718 (1976);
Activated carbon and chromium oxide: U.S. Pat. No. 4,192,822;
Aluminum fluoride which contains nickel and titanium: U.S. Pat. No. 4,069,266;
Chromium fluoride: U.S. Pat. No. 3,651,156;
Chromium oxyfluoride: G.B. Pat. No. 1,369,870;
Aluminum chloride: West German Pat. No. 1,618,588; and
Activated carbon: U.S. Pat. No. 2,981,763.